Sexual dimorphism: theory into practice, the answers

If you have put your skills to the test, here are the answers.  If you haven’t, look away now and read my previous post Sexual dimorphism: putting theory into practice.

  1. Clear cap golds: A is a male, B is a female.
  2. Non cap silvers: A is a female, B is a male.
  3. Broken cap golds: A is a male, B is a female.
  4. Broken cap golds: A is a female, B is a male.
  5. Clear cap silvers: A is a male, B is a female.
  6. Broken cap silver: A is a female, B is a male.
  7. The bird at the head of the article is a male.

Questions 1,2 and 3 were straightforward: the rowings being much more extensive in the hens.  Questions 4, 5 and 6 were difficult, not least because I deliberately selected photographs of birds that were as closely matched as possible.  I wouldn’t be surprised if some people are adamant that they have applied the theory and don’t understand how I could come to a different conclusion.  The answer to that is simple: I have the advantage of being able to see the complete bird.  Nevertheless, it’s only fair that I clarify some of the details.

4.  Broken cap golds.  Even though the difference is not that great, the hen has more extensive, and better defined, rowings.  The confusion arises because the male has exceptional rowings for a gold cock; you sometimes see gold hens with less.

5.  Clear cap silvers.  A tricky combination, both birds have good rowings and good colour, so how do you tell them apart?  The male has better colour and it extends further over the body; the cap is brighter. The hen is more frosty and her rowings are more extensive and have better definition.  Very good rowings for a silver cock Lizard canary; very good colour for a silver hen.  No wonder people get confused.

6.  Broken cap silvers.  I saved the best until last; a trick question designed to confuse.  Well done if you saw past the dissimulation.  The best way to reveal the truth is by posting photographs of the same birds taken from a different angle.

BCS MorF ans-fss

Their differences should now be clear.  In these photos you can see that the colour of the male is not only brighter, but also extends much further over the body.  She is more frosty, which is evident in the spangles, on the head, and around the neck.  He has outstanding rowings for a male, but they still do not match those of the female.

Footnote:

1   Well done to all those who were brave enough to put their judgements up for public scrutiny.  I’m impressed with their accuracy.

2.  All the photos in this series are subject to the limitations of digital photography.  The accuracy of the colours depends on the settings of the camera and the lighting conditions when the photos were taken.  Image quality will suffer if the bird moves or the light is poor.  I have also experimented with different background colours.  All these factors affect what you see on your screen (as does the colour calibration of the screen).  I do my best to produce realistic images, but some factors are beyond my control.

One thought on “Sexual dimorphism: theory into practice, the answers

  1. from those new pics I’m glad to see no error would have happened
    tks for the test – it was enjoyable even so judging from photos is not reliable

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